This invention relates generally to tape transport apparatus and, more particularly, to magnetic recording tape transport apparatus of the type having supply and take-up reels journaled on carriages that are movable to bring the reels into surface engagement with a capstan.
An example of a tape transport apparatus of this general type is disclosed in U.S. Pat. No. 4,023,748, issued in the name of D. L. Burdorf et al and entitled "Cassette Loading and Tape Tensioning System". The apparatus described therein includes a pair of movable pivot arms, each of which is pivoted at one end and carries a journaled reel of tape at the other end. The reels are urged by a spring force into compressive surface engagement with a capstan, whereby the recording tape is transferred from one reel, past a record/playback head, to the other reel. As the tape is so transferred, the diameters of the reels change accordingly and the pivot arms accommodate the changes by pivoting to maintain the outer layer of tape on each reel in contact with the capstan.
A major drawback arises when the aforedescribed prior art apparatus is used in portable devices, such as portable video tape recorders, which will be subject to shock or vibration. Shock and vibration forces will cause uncontrolled variations in the magnitude of the compressive force with which the reels are urged into engagement with the capstan, thereby introducing objectionable variations in the speed of the tape as it moves past the head. Moreover, substantial shock and vibration can frequently cause the reels to lose contact altogether with the capstan, sometimes resulting in the tape's becoming tangled and even breaking.
It will be appreciated from the foregoing that there is a definite need for a tape transport apparatus of the aforedescribed type that can withstand substantial shock and vibration without affecting the degree of compressive engagement with the capstan, thereby insuring a substantially constant tape speed. The present invention fulfills this need.